Tin-based esterification catalysts have been reported as catalysts for the carbamylation of polyols with carbamylating agents to form polycarbamates. The tin-based catalyst is non-specific in its activity, promoting both esterification and carbamylation reactions. For acrylic polyols, therefore, there is a simultaneous tendency for molecular weight to increase via branching. This is an undesirable result which is attributed to a side reaction of hydroxyl groups with the ester groups of the acrylic polymer. Accordingly, a carbamylation process which results in lower unwanted bXy-product and which does not substantially increase the molecular weight and/or viscosity would be desirable.